How much solar and battery does it take to run a 12V RV refrigerator off-grid? Pick your fridge below and the calculator sizes your solar panels, battery bank and charge controller. It uses each model's real-world daily energy use, not the nameplate amp draw.
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Why not just use the amp rating on the label?
A 12V compressor fridge doesn't run all the time. It cycles on and off to hold temperature, so a fridge rated at 8 amps might average only 2 to 3 amps across a day. Multiplying the label amps by 24 hours can double or triple your estimate and send you shopping for far more solar and battery than you need. Wherever the manufacturer publishes daily energy use, we use it. When they don't, we estimate from rated draw and typical compressor run time, and the calculator tells you which one you're looking at.
What changes the numbers most
- Heat: a compressor fridge can use about 50% more power on a 90°F day than on a 75°F day. Shade and good fridge ventilation help a lot.
- Winter sun: flat roof panels collect far less in winter, especially in northern states. If you camp in winter, size for winter.
- Battery type: you can use about 90% of a lithium battery's capacity but only about 50% of an AGM's, so an AGM bank needs to be nearly twice as big.
- Driving days: a DC-DC charger tops up your batteries from the alternator while you drive, so you need less solar.
Running lithium batteries? You'll want an MPPT controller with a LiFePO4 profile. Shop Lithium MPPT Charge Controllers. Not sure what fits your rig? Call us at 1-800-712-8822.